This invention relates to binders for holding loose leaf pages, and in particular to an improved mechanism for opening and closing binders.
A ring binder retains loose leaf pages, such as hole-punched papers, in a file or notebook. It features ring members for retaining the papers which may be selectively opened to add or remove papers, or closed to retain papers while allowing them to be moved along the ring members. Levers are typically provided on both ends of the binder for moving the ring members between the open and closed positions.
One drawback to ring binders of the prior art is that when ring members are being closed, they snap shut with a strong magnitude of force which can cause injury. When ring members are fully closed, that strong clamping force is necessary to securely lock the binder and prevent its unintentional opening. Unfortunately, that magnitude of force is also applied to the ring members while they are being opened or closed, causing difficulty in opening and closing the ring members, as well as the hazardous snapping action. Further, the clamping force within each ring is not uniform with the clamping force in other rings, causing uneven movement and potentially resulting in gaps on closed rings.